Improved Technique for Estimating the Number of Paths in a MIMO Context

The determination of full double-directional parameters of the mobile channel has received considerable attention these last years, one of the main applications being the optimization of MIMO systems. Dedicated high-resolution parameter estimation techniques usually need the prior knowledge of the number of paths (or sources), a wrong estimation leading to erroneous results of the channel parameters. In this paper, a pre-processing technique is proposed to improve the performances of source number detection algorithms based on the eigenvalues of the correlation matrix. This technique uses the interlacing property of the eigenvalues of a Hermitian matrix with those of its main submatrices.